In suspended ceiling structures, it is well known to suspend ceiling panels from a grid made of inverted T-beam support members. The inverted T-beam support members extend downward from a permanent ceiling structure, and enable the ceiling panels to be suspended therefrom in spaced relation to the permanent ceiling. The suspended ceiling panels are typically supported from the grid of inverted T-beam members in edge-to-edge relation, to form a decorative ceiling which conceals the supporting grid and the permanent ceiling from view. Moreover, the suspended ceiling is spaced from the permanent ceiling, to allow utility items such as pipes, ductwork, electrical wiring, etc. to be conveniently located in the hidden space between the decorative, suspended ceiling and the permanent ceiling.
There are several known ways to attach or suspend ceiling panels from inverted T-beam support members. Many of the known ways utilize spring clips or wires to attach and detach the ceiling panels from the inverted T-beam support members (see e.g. U.S. Pat. Nos. 4,463,537; 4,520,607).
Another known way of supporting ceiling panels from inverted T-beam support members is by means of torsion spring mounts. A series of U-shaped hardened wires are attached to the ceiling panels. The U-shaped wires are inserted into pre-punched slots along the horizontal edge of the inverted T-beam support members. The wires spring outward holding the ceiling panels against the horizontal face of the inverted T-beam support members. Such spring systems require special punching of the T-beam support members to receive the wires of each ceiling panel.
An example of a ceiling system which does not use wires or springs for suspending ceiling panels from a grid of inverted T-beam support members is disclosed in U.S. Pat. No. 4,760,677. The ceiling system comprises ceiling panels with specially formed flanges, slots and detents for enabling the ceiling panels to be attached and detached from the grid of inverted T-beam members.
Another ceiling system which does not use spring devices for attaching ceiling panels to inverted T-beam support members is shown in U.S. Pat. No. 4,736,564. The system includes ceiling panels which are attached to inverted T-beam supports by an up-and-side motion of the ceiling panels relative to the inverted T-beam support members to retain the ceiling panels on the inverted T-beam support members. However, such a system is "directional" in the sense that each panel has to be attached to the grid of inverted T-beam support members in a certain way relative to adjacent panels. Moreover, a ceiling panel near the center of the suspended ceiling cannot be removed from the grid of inverted T-beam support members without removing one or more adjacent ceiling panels. Thus, the ceiling panels have to be attached or detached from the grid of inverted T-beam members in a special order, especially when it is desired to attach or remove a central ceiling panel.